1. Field of the Invention
The invention relates to a knitted surface fastener comprising warp knitting structure and particularly to a knitted surface fastener having a pair of right and left sewn areas which are sewn to a surface fastener adherend and a surface fastener area which is disposed between the right and left sewn areas and which has a plurality of female engagement elements formed on one face of the surface fastener area.
2. Description of the Related Art
In general, a vehicle-use seat for an automobile etc. and an office chair are respectively configured that a cover material such as a seat cover is assembled to a cushion member which is formed by synthetic resin such as urethane foam into a predetermined shape so as to cover a surface of the cushion member. Further, in a vehicle-use seat and the like, the cover material is assembled so as to wrap the cushion member after a part of the cover material is fastened to a surface of the cushion member.
In this case, a male surface fastener with a plurality of hook-shaped or mushroom-shaped male engagement elements is attached to a surface of a cushion member as a fastening means in order to fasten a part of a cover material to the surface of the cushion member, and a female surface fastener with a plurality of loop-shaped female engagement elements, which are capable of engaging with and disengaging from the male engagement elements, is attached to a rear surface of the cover material.
In general, a knitted surface fastener manufactured by a knitting machine and a woven surface fastener manufactured by a weaving machine are known as a female surface fastener with loop-shaped female engagement elements. Here, a conventional general female knitted surface fastener is explained by referring to FIGS. 17 and 18.
A conventional female knitted surface fastener 70 includes a surface fastener area 72 which has a plurality of loop-shaped female engagement elements, and right and left sewn areas 71 which are disposed adjacently on right and left outer sides of the surface fastener area 72 and which are sewn to a surface fastener adherend such as a cover material.
Further, warp knitting structure of the knitted surface fastener 70 is composed of chain knitting yarns 75 (0-1/1-0) forming each wale of the surface fastener area 72 and the right and left sewn areas 71, tricot knitting yarns 76 (0-1/2-1) disposed on two wales adjacent to each other in the surface fastener area 72, and one weft insertion yarn 77 inserted in zigzags over all wales of the surface fastener area 72 and the sewn areas 71 (a whole width of the knitted surface fastener 70).
In this case, when the knitted surface fastener 70 is knitted by a warp knitting machine, a thin sheet-shaped insertion member is provided to be protruded from one surface of a wale forming face (e.g., a tape surface) at a position corresponding to between wales of the surface fastener area 72 in the warp knitting machine, and tricot knitting yarns 76 are knitted striding over the said insertion member. Accordingly, since a portion, which strides over the insertion member of the tricot knitting yarns 76, is brought into a loose condition after being knitted, loop-shaped female engagement elements are formed between each wale of the surface fastener area 72.
Further, multifilament yarns of polyester fiber are often utilized for the chain knitting yarns 75 forming the knitted surface fastener 70, the tricot knitting yarns 76, and weft insertion yarns 77. For example, polyester textured yarns with a thickness of 150-300 decitex are utilized for the chain knitting yarns 75 and the tricot knitting yarns 76, and polyester textured yarns with a thickness of 250-400 decitex are utilized for the weft insertion yarns 77.
In the knitted surface fastener 70 having the above warp knitting structure, female engagement elements by the tricot knitting yarns 76 are formed in the surface fastener area 72, and the right and left sewn areas 71 are firmly formed by the chain knitting yarns 75 and the thick weft insertion yarns 77 so as to be capable of preventing positional shifts of stitches in the sewn areas 71. Accordingly, the sewn areas 71 of the knitted surface fastener 70 can be firmly sewn to a surface fastener adherend such as a cover material, and the surface fastener area 72, which is sandwiched by the right and left sewn areas 71, can be firmly engaged with engagement elements of male surface fastener.
Meanwhile, for example, WO 2010/125675 (Patent Document 1) discloses a knitted or woven female surface fastener (fastening member). The knitted surface fastener being one of the embodiments of a surface fastener according to Patent Document 1 comprises right and left sewn areas which are sewn to the surface fastener adherend such as a cover material, a surface fastener area which is disposed between the right and left sewn areas and which has a plurality of female engagement elements, and a connection area which connects between each sewn area and the surface fastener area.
Further, warp knitting structure of the above knitted surface fastener is composed of the chain knitting yarns forming each wale of the surface fastener area and the right and left sewn areas, the tricot knitting yarns forming a plurality of loops which are disposed in the surface fastener area and become female engagement elements, and one weft insertion yarn inserted in zigzags over a whole width of the knitted surface fastener.
In the knitted surface fastener of Patent Document 1, when it is knitted by a warp knitting machine, the tricot knitting yarns of the surface fastener area are knitted by using a knitting needle which forms a wale composed of the chain knitting yarns in the warp knitting machine and a knitting needle which adjoins the said knitting needle and avoids being entangled with the chain knitting yarns. Accordingly, loop-shaped female engagement elements disposed in the surface fastener area are formed between wales composed of chain knitting yarns by needle loops in a side which is not interlaced with the chain knitting yarns of the tricot knitting yarns.
Further, the right and left connection areas, which connects between the surface fastener area and the right and left sewn areas, are composed of only weft insertion yarns which are inserted both in the surface fastener area and in the right and left sewn areas in common. The right and left connection areas are configured to have low knitting yarn density, compared to the right and left sewn areas.
In such a knitted surface fastener of Patent Document 1, a connection area, which is configured to have low yarn density so as to be easily deformed, is disposed between the surface fastener area which has a plurality of female engagement elements and the right and left sewn areas which are sewn to a surface fastener adherend. Accordingly, the knitted surface fastener can relatively easily displace the surface fastener area against the right and left sewn areas owing to deformation of the connection area by using movement and elasticity or the like of composition yarns which form the connection area.
Accordingly, when the cover material attaching the knitted surface fastener of Patent Document 1 is fastened to the cushion member attaching a male surface fastener, for example even in a case that a fastening position of the cover material is shifted or in a case that a variation in dimensions and shapes occurs at each cover material, a prominent effect that wrinkling occurrence at the cover material, which attaches the knitted surface fastener, can be effectively prevented owing to relative displacement of the surface fastener area of the knitted surface fastener against the right and left sewn areas, can be obtained.
In addition, as the other embodiment of a surface fastener according to Patent Document 1, a knitted surface fastener which is composed of the above warp knitting structure as shown in FIG. 19 is described.
A knitted surface fastener 80 as shown in FIG. 19 also comprises right and left sewn areas 81 which are sewn to a surface fastener adherend such as a cover material, a surface fastener area 82 which is disposed between the right and left sewn areas 81 and which has a plurality of female engagement elements, and a connection area 83 which connects between each sewn area 81 and the surface fastener area 82.
Further, warp knitting structure of the surface fastener area 82 in the knitted surface fastener 80 is composed of chain knitting yarns 85 forming each wale, tricot knitting yarns 86 forming a plurality of loops to become female engagement elements, and one first weft insertion yarn 87 inserted in zigzags over the whole surface fastener area 82 (all wales of the surface fastener area 82).
Further, in the above knitted surface fastener 80, warp knitting structure of the sewn areas 81 is composed of the chain knitting yarns 85 forming each wale and second weft insertion yarns 88 inserted in zigzags over the whole sewn areas 81 (all wales of the sewn areas 81). In addition, warp knitting structure of a connection area 83 is non-densely composed of only third weft insertion yarns 89 inserted in order to connect between a wale, which is disposed at the outer edges of the surface fastener area 82, and a wale, which is disposed at the inner edges of the sewn areas 81, compared to that of the sewn areas 81.
In the knitted surface fastener 80 which is composed of the above first weft insertion yarns 87 to the third weft insertion yarns 89, since the connection area 83 which are configured to have low yarn density is disposed between the surface fastener area 82 and the right and left sewn areas 81, the surface fastener area 82 can be relatively easily displaced against the right and left sewn areas 81 and the same effect as the above can be obtained.
In addition, the knitted surface fastener 80 as shown in FIG. 19 is manufactured by concurrently knitting the surface fastener area 82, the right and left sewn areas 81, and the right and left connection areas 83. Alternatively, it is also possible to manufacture it, for example, by previously and separately knitting the surface fastener area 82 and the right and left sewn areas 81, subsequently knitting the third weft insertion yarns 89 in order to connect between the obtained surface fastener area 82 and the right and left sewn areas 81, and forming the right and left connection areas 83.    Patent Document 1: WO 2010/125675